In North Koreas heavily militarised society, even learning the periodic table can be done at the barrel of a gun.
"The young students enjoy it," said the assistant, picking up a model rifle and aiming it at the familiar table of elements projected on a screen about 10 feet away.
A hit on Po brings up an explanation of Polonium -- its discovery, properties and uses.
The shooting range is one of a number of teaching aids housed in the Science and Technology Center, a vast complex built in the shape of an atom on a river islet in Pyongyang.
Opened earlier this year, the centre shares characteristics common to other grandiose projects constructed in the showcase capital under the direct orders of supreme leader Kim Jong-Un, using scarce money and resources siphoned from North Korea's threadbare economy.
It was built at lightning speed -- just over 10 months using soldier labour -- looks impressive, and is almost eerily empty.
The complex reportedly receives several thousand visitors a day, but on a recent Saturday afternoon, only a few dozen of the more than 3,000 computer console study stations were occupied -- several of those by members of staff.
Like other prestige projects, the centre is as much a symbol of intent as anything else.
Wealth and power
In numerous speeches and statements, including a keynote address to a rare party congress in May, Kim has put science and technology front and centre of the effort to build a "rich and powerful fatherland."
The power element is firmly focused on national defence, and a science-based weapons system ranging from cyber warfare to a sophisticated nuclear deterrent.
The country's nuclear and missile scientists are treated as national heroes, feted with personal congratulations from the top leadership and rewarded with modern high-rise apartments in Pyongyang and multiple other benefits for themselves and their families.
The Sci-Tech Center's main structure is built around a large mock-up of the North's Unha 3 rocket -- a satellite launcher seen as a prototype for an eventual inter-continental ballistic missile capable of delivering a nuclear warhead to the mainland United States.
Pyongyang insists the rocket's uses are purely scientific and space-based.
On the cyber warfare front, the North has already proved its technical capabilities, launching a damaging attack on South Korean banks and broadcasters in 2013 and blamed by Washington for an audacious hacking assault on Sony Pictures the following year.
'World-class' cyber warriors
In testimony to the US Senate Armed Services Committee in April, the newly-appointed commander of US forces in South Korea, General Vincent Brooks, said the North's elite cyber units "are among the best in the world and the best organised."
This in a country where access to the full internet is the privilege of an elite few.
The Sci-Tech complex's computer consoles are segregated, with those in the main hall only capable of accessing a home-page hosted on an internal server with a limited menu of subjects ranging from children' cartoons to educational material.
Users over the age of 17 and with the required permission, can surf the North's tightly-controlled, closed-network intranet system, allowing access to state media and some officially approved sites.
There are also links to North Korean university e-libraries and large wall posters boast -- or at least suggest -- the availability of well-known Western scientific databases like Elsevier and Springer.
The intranet runs on an indigenously developed Linux-based operating system, Red Star.
Niklaus Scheiss and Florian Grunow, two German researchers who downloaded and conducted an exhaustive analysis of Red Star, described it as the "wet dream of a surveillance state."
The system notes and reacts to any attempt to tinker with its core functions and creates tabs, or "watermarks," on the files of a computer or any USB stick connected to it.
The purpose, Scheiss and Grunow told a conference in Hamburg last year, is to track any user who created, possessed or opened any particular file.
It's a powerful tool in a country where unauthorised material, including foreign films, news articles or music are often shared illicitly using USB sticks or other data cards.
Visitors to the Sci-Tech centre are issued temporary ID cards that allocate and log them in and out of a specific console.
"I wanted to put into action our Dear Leader's words to place our country at the forefront of science and technology," Ri told AFP.
Ordinary North Koreans usually express only officially-sanctioned views when questioned by foreign news organisations.